The present invention relates to means for memorizing an accompaniment passage and then playing back the passage whenever desired by the performer.
To store the absolute address for each note of the keyboard would require a full six bit word, in the case of a sixty-one note manual, and to store a four note chord, then four times as much storage capacity would be required, thereby resulting in a rather expensive and inefficient system to perform the desired function. Such capacity is not necessary, however, because it is not possible for the player to span the entire keyboard when playing a single accompaniment chord without using two hands and, from a practical standpoint, the occasion for playing such a chord would be quite rare in normal musical compositions.
The system of the present invention relies on the principle that starting with the highest note played in the accompaniment, the next note lower will not be greater than seven notes away and no note will be more than seven notes away from the notes on either side of it.